Soil geochemical characteristics of landscapes within the upper reaches of the Klyazma river

Problem Statement and Purpose. The problem of environmental pollution with various potentially dangerous substances and, first of all, heavy metals, the impact of which will be carried out for many years, is the most important for environmental geochemistry. Despite the material accumulated in the literature, the forms of finding and mobility of trace elements in soils remain insufficiently researched; forms of migration of chemical elements in soil solutions, natural waters, entry into vegetation. The study of heavy metals in biomass systems of urban areas and their ecological assessment require systematic, comprehensive research. Establishing the relationship between the content of chemical elements in vital natural environments for humans is of particular importance. The main purpose of this article is to study the patterns of distribution of trace elements in the main types of soils, vegetation and forms of their migration in natural waters, background and technogenically polluted areas of the Forest- Steppe Zone. Data & Methods. The measurement of the content of heavy metals in soil and natural water samples was performed using the method of mass spectrometry with inductively coupled plasma (ICP-MS) on the Element‑2 analyzer (Germany). The forms of microelements in soil samples were determined by the method of successive extractions. The forms of migration of trace elements in natural waters were determined using mathematical modeling methods using specialized software tools GEMs v.3.2 and Hydra&Medusa. Results. The regularities of the distribution of microelements in soils, natural waters, and vegetation in conditionally clean and technogenic landscapes of the Forest-steppe zone of Ukraine were studied. The distribution of microelements in soils is determined by their physical and chemical properties, mineralogical and geochemical parameters of soil-forming rocks, landscape and technogenica conditions of the studied territories. Analytical studies were conducted to determine the mobile forms of microelements in soil solutions. Data were obtained on the regularities of the distribution of heavy metals in the soils of conditionally clean territories and the natural park of the NNP «Nizhnyosulsky», as well as their content in the vegetation of park landscapes. The gross content of Pb, Cu, Ti, Cr, V in the soils of the studied territory of the NPP «Nizhnyosulsky» is higher than the background values. The bio-inert systems of technogenic landscapes of the city of Brovary and Kyiv landfill № 5 were studied. It was established that the emissions of industrial enterprises of various profiles significantly change the geochemical background of metals in the analyzed soils of the city of Brovary. In these soils, the content of heavy metals, which are in the exchangeable and easily exchangeable fractions, increases and their mobility increases compared to the background ones. The highest level of soil contamination is observed on the territory of landfill № 5. Using the method of thermodynamic modeling, data on the forms of migration of microelements in soil solutions of technogenically polluted soils, natural waters (surface and underground) were obtained. Migration of heavy metals in soil solutions is carried out mainly in the form of free cations and dissolved organometallic complexes. The increased content of Mn, Cu, Co, Fe in the dry residue of the surface water of landfill № 5 was determined, which does not meet the sanitary standards for the discharge of wastewater into open waters. Pollution of surface waters by sewage with a high content of primarily organic toxicants: nitrates, vchlorides, was also found. The peculiarities of the microelement composition of drinking groundwater in the territory of Korostyshiv district of Zhytomyr region were studied. The dynamics of changes in the amount of total mineralization, the content of ions Ca2+, Mg2+, SO42–, Cl– in the aquifer of the fractured zone of crystalline rocks and their weathering crust were analyzed. A high positive correlation was found between the concentrations of Mg2+, SO42–, Cl– and their normalized indicators by the amount of water withdrawal. The obtained results testify to the significant role of the anthropogenic factor in the formation of the chemical composition of the studied groundwater. A comparison of the biologically significant concentrations (BSC) of the main microelements of groundwater with their content in water samples determined during the study allowed us to identify peculiarities: in the studied waters, an excess of such elements as Sr and Ba is observed. Instead, insufficient amounts of elements such as Li, V, Mn, Co, Ni, Cu, Zn, As, Cd and Pb were found. Based on the obtained results, conclusions were made about the presence of risks of some trace element diseases in the studied territory.

This review presents geochemical and medical-ecological information on the content, distribution, and accumulation of rare-earth elements in soils of technogeochemical anomalies. The significance of V.I. Vernadskii’s ideas in development of the theory of the chemical elements atoms migration in the biosphere is demonstrated. Specific features of the atomic structure of rare-earth elements, determining their chemical and toxic properties, are presented. Natural mineral concentrators of scandium, ytterbium, and the lanthanide group are considered in detail. Distribution patterns for these chemical elements in mining deposits and soils of technogenic impact zones are analyzed. Characteristic reactions of rare-earth elements on the soil-formation process and their interaction with various soil compounds (fractionation, complexation) are presented. Characteristics of the Cherepovets technogeochemical anomaly, contaminated with barium, lanthanum, and cerium are given in more detail. The problem of soil profile contamination in tailings dumping sites is discussed. The issue of biological fixation of rare-earth elements by plants and main directions of their migration in the natural environment are discussed. It is shown that soils of urbanized territories are a depositing medium for such elements and carry a great environmental and technogenic burden. Data are provided concerning ways to reduce the toxic effects of rare-earth elements on the environment and measures to control soil pollution in order to prevent the occurrence of environmentally caused diseases in humans.

The microelement composition (Pb, V, Cr, Zn, Mn, Cu) of the mountain-podzolic brown earth soils of the Chornohir and Marmarо reserve massifs of the Carpathian Biosphere Reserve was determined: background, under wet and dry moss (Sphagnum palustre L.). The increased content of trace elements (Cu, V, Zn, Mn) in the upper soil layer of the Chornohir massif was determined, which is explained by the presence of a clay component, and the lower content in the Marmaros massif — the presence of carbonates. Ranked series were constructed by the dispersion coefficient of microelements in soils covered with wet and dry moss Sphagnum palustre L. It was established that the soil under dry moss is practically not depleted of microelements, but in the presence of rains it becomes wet again and the sorption process resumes. It was found that the soils under the wet moss of the Chornohir massif are most depleted in Mn, Cu, and Zn; and the Marmaros massif — Mn, Pb, and V. The geochemical behavior of the studied microelements in soils under wet moss was analyzed. It was concluded that wet moss has a selective ion exchange, is a geochemical barrier, and that is why lithochemical search and monitoring works should be carried out in the areas covered with wet moss, taking into account the established features.

Работа посвящена изучению особенностей состава почвенного поглощающего комплекса (ППК) по элементам рельефа балочного водосбора. Целью работы является выявление зависимости ППК от степени развития и характера водной эрозии и аккумуляции. Для достижения поставленной цели был решен ряд задач: проведение площадной почвенно-эрозионной съемки балочного водосбора; определение физико-химических и физических свойств почв по ГОСТированным и общепринятым методикам; сравнительный анализ поглотительных свойств почв по элементам рельефа балочного водосбора. Высокая степень эродированности территории определяет актуальность исследования поглотительных свойств почв, подверженных смыву и намыву. Объектом исследования являются почвы водосборной площади балки «Лог Репный». Согласно почвенно-эрозионному районированию Воронежской области объект исследования расположен в Семилукско-Нижнедевицком районе. Наблюдалось обеднение всего профиля почв водораздельных склонов и берега балки илистой фракцией за счет влияния эрозии почв и денудации. На днище балки было зафиксировано обогащение верхней части почвенного профиля илистой фракцией под влиянием аккумуляции почвенного материала, смываемого с вышележащих склонов. Поглотительная способность почв различных элементов рельефа водосборной площади балки «Лог Репный» может быть охарактеризована с помощью величины суммы поглощенных оснований. Наибольшая сумма поглощенных оснований наблюдалась на водораздельном плато (15.73 ммоль/100 г почвы). На берегу балки в условиях влияния процесса денудации зафиксировано уменьшение суммы поглощенных оснований в 2.5 раза. На днище балки в зоне преимущественной аккумуляции смываемого со склонов почвенного материала сумма поглощенных оснований была ниже, чем на водоразделе в 1.4 раза. Это связано с различным содержанием илистой фракции в этих почвах. Так, в почвах водоразделов илистая фракция составляла 24.8%, на берегу балки ее содержание было в 2.5 раза ниже, а на днище балки вновь возрастало до 22.4 %. Установлена зависимость суммы поглощенных оснований почв от перераспределения илистой фракции под влиянием эрозии и аккумуляции почв.

Specific features of the transformation of humic substances in particle-size fractions of drained soddy-podzolic soils were studied on a field (12 ha) of the Experimental and Educational Center of Lomonosov Moscow State University in Moscow oblast. The field had a clearly pronounced microtopography. Surface-gleyed soddy-podzolic soils (Albic Stagnic Glossic Retisols (Loamic, Aric, Ochric)) of microdepressions with excessive surface moistening and nongleyed soddy-podzolic soils (Albic Glossic Retisols (Loamic, Aric, Ochric)) of elevated positions were examined. These soils were studied before the field drainage and during 25 years after drainage works in the periods differing in conditions of humification and with due account for not only drainage works but also other factors, such as topography and agrotechnology and their joint action. The specificity of transformation of humic substances in the soils and their particle-size fractions was analyzed in the basis of data on the organic carbon content, group and fractional composition of humus, the intensity of individual stages of humification (the neoformation of humic acids and the formation of humates), and the optical density of the fractions of humic acids. The results of the study of these properties in the fine soil fractions (<50 μm) made it possible to assess the response of the clay (<1 μm) and silt (1–5, 5–10, 10–50 μm) fractions to changes in the ecological situation and the role of separate particle-size fractions in the degradation of humus under adverse impacts. Overall, a clear tendency toward worsening of the humus quality was observed in both soils during the 25-year-long period, which is related to the long-term (20 years) agricultural use of the reclaimed field without application of agrochemicals. The features of humus degradation were mainly manifested in the finest (<10 μm) fractions with a general decrease in the humus content, slowing down of the formation of humic acids and humates, and considerable loss of humic acids, including their agronomically valuable fractions HA1 and HA2. The degradation of humus quality in the clay fraction was largely due to the impact of the reclamation (drainage) factor; the degradation of humus quality in the fine and medium silt fractions was mainly due to the negative changes in the agricultural background. Among negative consequences of the worsening humus quality, the lowering of soil fertility, ecological sustainability, and productivity of agrocenoses should be noted.

Geochemical post-pyrogenic soil changes are one of the most important factors in determining the state of the forest ecosystem. For the first time the content of microelements (Hg, As, Ba, Mg, Mn, Mo, Cd, Co, Cr, Cu, Pb, Zn, V, Ni) in post-pyrogenic sod-podzolic soils under the pine forest of Zhytomyr Polissya (Ukraine) was determined by the ICP-MS method. The study is based on a comparison of the content of trace elements in the sod-podzolic soils of the background area and burnt areas (grassland fire in 2019). The analysis of microelements in the soil profile of the burned and background areas to a depth of 10 cm (after 1 cm) and set the limit - 3-5 cm (humus-eluvial horizon), after which you can record the accumulation or scattering of elements after a fire on the surface. By calculating the percentage change (relative to background soils), intensive accumulation (more than 20%) of elements in post-pyrogenic soils - Cu, Ni, Co, V and moderate accumulation (up to 10%) - Pb, Mo, Mg, Ba, Cr and intensive scattering - Hg, As, Cd, Zn, Mn. The increase in the pH of post-pyrogenic soils (from 4.2 to 7.5) was determined, spatial map-schemes were constructed, due to which the direction of the fire was revealed - from the south-east to the north-west. The change of the content of ionic forms of metals (Cu, Pb, Zn, Mn) in the soil solution at different pH values (from 4 to 8 with a step of 0.2) is modeled (PHREEQC program) and the current trend is revealed: Pb - linear dependence, Cu, Zn, Mn is polynomial. The pH limits are calculated, where there are free forms of metals that enter the plants: Pb 3.9-8.2; Zn 5.5-7.5; Cu 5-8.2; Mn 5-11.5. The post-fire transformation of soils was revealed, which is expressed in the increase of pH (before the fire - 4.2-4.8; after the fire - 6.5-7.2; a year after the fire - 4.5-5.5). The obtained results confirmed the need for geochemical monitoring of post-pyrogenic soils for ecosystem restoration and plant biodiversity.

The investigation of the contents and distribution patterns of elements in soils constitutes an indispensable part of environmental science and soil geochemistry. This paper deals with the contents of transitional and rare earth elements in paddy soils and their relations to the geochemical characteristics.

The article discusses the features of changes in the microelement composition of urban soils of the Stavropol agglomeration under the influence of urban genesis. Urban genesis, as a combination of technogenesis and landscape genesis on the territory of urban development, affects many aspects of soil functioning. Their physical properties, chemical composition, structure and mutual arrangement of genetic horizons change. Of particular relevance is the establishment of the specifics of the transformation of the microelement composition of urban soils in connection with the environmental hazard of a significant amount of trace elements classified as heavy metals. The city of Stavropol is characterized by a complex type of development, which combines one-story and multistory buildings, industrial infrastructure, and household facilities. This leads to the formation of multidirectional flows of pollutants, most of which enters the soil or subsoils. The presence of a clearly defined slope relief in the central part of the city causes the redistribution of silty fractions with water and air flows in an easterly direction. At the same time, differences in the nature of soil-forming rocks for different parts of the city largely change the pattern of differentiation of microelements in the soils of the city, associated with the peculiarities of their fixation in the composition of soil compounds. For the northwestern and central regions of the city, where Sarmatian limestone-shell rocks are exposed to the surface, calcium carbonates play a decisive role in the binding of trace elements in soils. In the soils of the southwestern and southern districts of the city, formed on loess-like loams, organomineral complexes of humic acids are of great importance in fixing microelements. In the bottoms of river valleys and gullies, formed by erosion products of Sarmatian clays, microelements in soils are present in silty fractions. Under the forest parks of the city, several dominant phases - carriers of microelements in soils are formed, depending on the predominance of one or another type of soil-forming deposits in different parts of the forest. In general, the features of the fixation of microelements in the soils of the Stavropol urban agglomeration are determined both by the natural characteristics of the territory and the specifics of the anthropogenic impact on the soil cover of pollutant flows.

Standard Rates of Content of Chemical Elements in the Soil: International Experience and Use for Western Siberia

Soil profiles were collected in three salt marshes with different plant species (i.e. Phragmites australis, Tamarix chinensis and Suaeda salsa) in the Yellow River Delta (YRD) of China during three seasons (summer and fall of 2007 and the following spring of 2008) after the flow-sediment regulation regime. Total elemental contents of As, Cd, Cu, Pb and Zn were determined using inductively coupled plasma atomic absorption spectrometry to investigate temporal variations in trace elements in soil profiles of the three salt marshes, assess the enrichment levels and ecological risks of these trace elements in three sampling seasons and identify their influencing factors. Trace elements did not change significantly along soil profiles at each site in each sampling season. The highest value for each sampling site was observed in summer and the lowest one in fall. Soils in both P. australis and S. salsa wetlands tended to have higher trace element levels than those in T. chinensis wetland. Compared to other elements, both Cd and As had higher enrichment factors exceeding moderate enrichment levels. However, the toxic unit (TU) values of these trace elements did not exceed probable effect levels. Correlation analysis showed that these trace elements were closely linked to soil properties such as moisture, sulfur, salinity, soil organic matter, soil texture and pH values. Principal component analysis showed that the sampling season affected by the flow-sediment regulation regime was the dominant factor influencing the distribution patterns of these trace elements in soils, and plant community type was another important factor. The findings of this study could contribute to wetland conservation and management in coastal regions affected by the hydrological engineering.

The aim was to study the distribution of macro-and microelements in the main urban ecosystems of Karelia. Methods. Samples of soil, vegetation, surface water, sediments and biota (fish) were taken. In total, 300 samples were collected. The analysis of the material was carried out using epithermal instrumental neutron activation analysis (INAA), x-ray spectral analysis (XRF), and atomic absorption spectrometry (AAS) with "cold steam" and inductively coupled plasma spectrometry (ICP-MS). Concentration of 32 chemical elements in soil, birch leaves, sediments, water and biota (fish) was determined. Results. The distribution of macro- and microelements in soil and vegetation of these main cities of Karelia was determined. Geochemical profiles of distribution of elements in soils and vegetation were constructed. Concentration of heavy and toxic metals in the samples of water and sediments was close to the background values. High concentration of mercury in the muscles of predatory fish was found (CHg = 0.2÷0.3 mcg/kg). Conclusions. The levels of total accumulation of heavy and toxic metals in the soil of Petrozavodsk are classified as hazardous (Zc = 56), and soil pollution in Pitkyaranta, Sortavala and Suoyarvi is considered moderately dangerous (Zc = 15-31). A high degree of correlation between the concentration of elements in the soil and birch leaves was found. The water in lake Ladoga, lake Onega, and lake Suoyarvi in terms of the concentration of the elements presented in the article meets the Russian standards for drinking water.

A lysimetric experiment has made it possible to trace changes in the fine and medium silt fractions of soils developing from the noncalcareous mantle loam under typical phytocenoses of the southern taiga zone during a 33-year-long period. The silt fractions were separated by the Gorbunov method, and their mineralogical composition was analyzed by X-ray diffractometry. The fine silt fraction consists of quartz, kaolinite, chlorite, hydromica, smectite, and feldspars. The medium silt fraction consists of quartz, kaolinite, mica, and feldspars. In both fractions, the content of feldspars in the upper horizons has increased in comparison with the initial parent material due to the physical disintegration of coarser fractions. The chemical decomposition of mica has been registered in the layer of 10–30 cm. In lysimeters under artificially planted mixed forest cenoses, acidic hydrolysis may take place at this depth. Cryogenic processes play an important role in the soil formation at the early stages.

Total concentrations of Ti, Cr, Mn, Ni, Cu, Zn, Rb, Sr, and Pb as well as soil granulometric texture were studied for three plot sites representing different geomorphologic units of the southwestern part of Western Siberia: periphery of the upland Tobolsky Mainland, Ishim plain, Turinskaya plain. Interregional difference in the relationship by and among the content of trace elements and particle size distribution of soil horizons is established. Thus, for the soils of Turinskaya plain such interrelations are not observed. For the soils of Ishim Plain moderate negative correlation between Pb concentrations and medium silt, as well as average positive correlations between Zn and fine sand, coarse sand and Pb are found. For the soils of the high terraces of the Irtish and periphery of Tobolsky Mainland interface zone moderate positive correlations between contents of Ti, Zn, Sr and fine sand, weak positive ones between Rb and medium sand, moderate negative ones between Zn and clay, Ti, Ni, Cu, Zn, Rb, Sr, and fine dust, Ti, Cu, Zn, Rb, Sr and medium silt are observed. Consequently, properties and genesis of local parent rocks are significant factors for distribution and accumulation of trace elements in the soils of the southern taiga; at the same time, the processes of bioaccumulation in thick humus horizons of dark gray soils and chernozems apparently play an important part in accumulation and migration of trace elements in forest-steppe soils of Ishim and Turinskaya plains.

Reference values for potentially harmful elements in soils from Atlantic Rainforest, Brazil

Using the alkaline fly ash after combustion of lignite as the acid soils neutralizer is a technique known for decades. Due to many disadvantages of the direct fly ash application it is sought to modify this material prior to its use. The process of fly ash modification in the magnetic activator involved breaking up fly ash to small grain sizes in order to obtain a material with a very large specific surface and modified properties. The purpose of the research was to compare the properties of unmodified fly ash with those of ash modified in the magnetic activator in terms of its usefulness in the neutralization of acidic soils. Unmodified fly ash was classified as a medium-grained calciferous material. The basic components of ash were silicates (33.28% of SiO2) and calcium compounds (31.26% of CaO). It has a low heavy metal content falling within a range characteristic of coal ash and meeting soil quality standard requirements. As a result of activation, the following changes were obtained in the properties of modified ash compared with unmodified ash: sand fraction content – reduced to 0.40, silt fraction content – increased by 1.40, silt fraction content – increased by 1.68, content of the sum of the dust and silt fractions – increased by 1.49, specific surface – increased by 1.65, fineness – reduced by 0.48. Modification of fly ash in the magnetic activator was found to have improved the physical properties of ash as acidic soil neutralizer, and its chemical properties make such an application possible.